/*
 * Copyright 2007 Kasper B. Graversen
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.bytestorm.isp;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import java.util.TimeZone;

import org.supercsv.cellprocessor.CellProcessorAdaptor;
import org.supercsv.cellprocessor.FmtDate;
import org.supercsv.cellprocessor.ift.DateCellProcessor;
import org.supercsv.cellprocessor.ift.StringCellProcessor;
import org.supercsv.exception.SuperCsvCellProcessorException;
import org.supercsv.util.CsvContext;

/**
 * Converts a String to a Date using the {@link SimpleDateFormat} class. If you want to convert from a Date to a String,
 * use the {@link FmtDate} processor.
 * <p>
 * Some example date formats you can use are:<br>
 * <code>"dd/MM/yyyy"</code> (parses a date formatted as "25/12/2011")<br>
 * <code>"dd-MMM-yy"</code> (parses a date formatted as "25-Dec-11")<br>
 * <code>"yyyy.MM.dd.HH.mm.ss"</code> (parses a date formatted as "2011.12.25.08.36.33"<br>
 * <code>"E, dd MMM yyyy HH:mm:ss Z"</code> (parses a date formatted as "Tue, 25 Dec 2011 08:36:33 -0500")<br>
 * <p>
 * This processor caters for lenient or non-lenient date interpretations (the default is false for constructors without
 * a 'lenient' parameter). See {@link SimpleDateFormat#setLenient(boolean)} for more information.
 * <p>
 * If you don't wish to use the default Locale when parsing Dates (your data is formatted for a different Locale), then
 * use the constructor that accepts a Locale.
 * 
 * @author Kasper B. Graversen
 * @author James Bassett
 */
public class ParseDateEx extends CellProcessorAdaptor implements StringCellProcessor {
    
    private final String dateFormat;
    
    private final boolean lenient;
    
    private final Locale locale;
    
    private final TimeZone tz;
    
    /**
     * Constructs a new <tt>ParseDate</tt> processor which converts a String to a Date using the supplied date format.
     * This constructor uses non-lenient Date interpretation.
     * 
     * @param dateFormat
     *            the date format to use
     * @throws NullPointerException
     *             if dateFormat is null
     */
    public ParseDateEx(final String dateFormat) {
        this(dateFormat, false);
    }
    
    /**
     * Constructs a new <tt>ParseDate</tt> processor which converts a String to a Date using the supplied date format.
     * 
     * @param dateFormat
     *            the date format to use
     * @param lenient
     *            whether date interpretation is lenient
     * @throws NullPointerException
     *             if dateFormat is null
     */
    public ParseDateEx(final String dateFormat, final boolean lenient) {
        super();
        checkPreconditions(dateFormat);
        this.dateFormat = dateFormat;
        this.lenient = lenient;
        this.locale = null;
        this.tz = null;
    }
    
    /**
     * Constructs a new <tt>ParseDate</tt> processor which converts a String to a Date using the supplied date format
     * and Locale.
     * 
     * @param dateFormat
     *            the date format to use
     * @param lenient
     *            whether date interpretation is lenient
     * @param locale
     *            the Locale used to parse the date
     * @throws NullPointerException
     *             if dateFormat or locale is null
     */
    public ParseDateEx(final String dateFormat, final boolean lenient, final Locale locale, final TimeZone tz) {
        super();
        checkPreconditions(dateFormat, locale);
        this.dateFormat = dateFormat;
        this.lenient = lenient;
        this.locale = locale;
        this.tz = tz;
    }
    
    /**
     * Constructs a new <tt>ParseDate</tt> processor which converts a String to a Date using the supplied date format,
     * then calls the next processor in the chain. This constructor uses non-lenient Date interpretation.
     * 
     * @param dateFormat
     *            the date format to use
     * @param next
     *            the next processor in the chain
     * @throws NullPointerException
     *             if dateFormat or next is null
     */
    public ParseDateEx(final String dateFormat, final DateCellProcessor next) {
        this(dateFormat, false, next);
    }
    
    /**
     * Constructs a new <tt>ParseDate</tt> processor which converts a String to a Date using the supplied date format,
     * then calls the next processor in the chain.
     * 
     * @param dateFormat
     *            the date format to use
     * @param lenient
     *            whether date interpretation is lenient
     * @param next
     *            the next processor in the chain
     * @throws NullPointerException
     *             if dateFormat or next is null
     */
    public ParseDateEx(final String dateFormat, final boolean lenient, final DateCellProcessor next) {
        super(next);
        checkPreconditions(dateFormat);
        this.dateFormat = dateFormat;
        this.lenient = lenient;
        this.locale = null;
        this.tz = null;
    }
    
    /**
     * Constructs a new <tt>ParseDate</tt> processor which converts a String to a Date using the supplied date format
     * and Locale, then calls the next processor in the chain.
     * 
     * @param dateFormat
     *            the date format to use
     * @param lenient
     *            whether date interpretation is lenient
     * @param locale
     *            the Locale used to parse the date
     * @param next
     *            the next processor in the chain
     * @throws NullPointerException
     *             if dateFormat, locale, or next is null
     */
    public ParseDateEx(final String dateFormat, final boolean lenient, final Locale locale, final TimeZone tz, final DateCellProcessor next) {
        super(next);
        checkPreconditions(dateFormat, locale);
        this.dateFormat = dateFormat;
        this.lenient = lenient;
        this.locale = locale;
        this.tz = tz;
    }
    
    /**
     * Checks the preconditions for creating a new ParseDate processor with a date format.
     * 
     * @param dateFormat
     *            the date format to use
     * @throws NullPointerException
     *             if dateFormat is null
     */
    private static void checkPreconditions(final String dateFormat) {
        if( dateFormat == null ) {
            throw new NullPointerException("dateFormat should not be null");
        }
    }
    
    /**
     * Checks the preconditions for creating a new ParseDate processor with date format and locale.
     * 
     * @param dateFormat
     *            the date format to use
     * @param locale
     *            the Locale used to parse the date
     * @throws NullPointerException
     *             if dateFormat or locale is null
     */
    private static void checkPreconditions(final String dateFormat, final Locale locale) {
        if( dateFormat == null ) {
            throw new NullPointerException("dateFormat should not be null");
        } else if( locale == null ) {
            throw new NullPointerException("locale should not be null");
        }
    }
    
    /**
     * {@inheritDoc}
     * 
     * @throws SuperCsvCellProcessorException
     *             if value is null, isn't a String, or can't be parsed to a Date
     */
    public Object execute(final Object value, final CsvContext context) {
        validateInputNotNull(value, context);
        
        if( !(value instanceof String) ) {
            throw new SuperCsvCellProcessorException(String.class, value, context, this);
        }
        
        try {
            final SimpleDateFormat formatter;
            if( locale == null ) {
                formatter = new SimpleDateFormat(dateFormat);
            } else {
                formatter = new SimpleDateFormat(dateFormat, locale);
            }
            formatter.setLenient(lenient);
            if (null != tz) {
                formatter.setTimeZone(tz);
            }
            final Date result = formatter.parse((String) value);
            return next.execute(result, context);
        }
        catch(final ParseException e) {
            throw new SuperCsvCellProcessorException(String.format("'%s' could not be parsed as a Date", value),
                context, this, e);
        }
    }
}
